Available from Release 5. Screen Overlay and Screen Backdrop are new in Release 5. Organisations move to Release 5 on their release weekend, from 9 October.
Screen Overlay and Screen Backdrop are new in Release 5. Some content belongs on every scene: a logo, a footer, a menu or an ambient background. Add it once to a Screen Overlay or a Screen Backdrop, and it shows on every scene of that screen. When it needs to change, you change it in one place.
What they are
Screen Overlay (new in Release 5): always visible in front of every scene on that screen. Use it for logos, footers or navigation.
Screen Backdrop (new in Release 5): sits behind every scene on that screen. Its content shows through wherever a scene has no background of its own.
From back to front, a screen shows:
The Screen Backdrop
The scene background
The scene's assets
The Screen Overlay
Add a Screen Overlay or Screen Backdrop
In the left rail, open Screen options (⋯ next to the screen name).
Choose Add Screen Overlay or Add Screen Backdrop.
It appears above the scene list of that screen, with its own icon. Each screen can have one Screen Overlay and one Screen Backdrop. They can only be added and removed in the Base Setup.
Add content
Select the Screen Overlay or Screen Backdrop in the left rail.
Add media or text as you would in a scene, or paste assets you copied from a scene.
Its assets have the same settings as scene assets: Size & Position, Content, Text style, Appearance, Video or Audio, Web and Playback. When you paste assets here, their on-click actions and triggers are not copied.
Replace media, under Content, swaps an image or video for another image or video from My media or the Company Library, in the same frame. A name you gave the asset stays. If you replace an image with a video, turn on Autoplay, otherwise the video won't start by itself.
Move content to another screen
Copy and paste Screen Overlay and Screen Backdrop assets onto another screen, or drag them to another screen.
Undo and redo
Undo (Ctrl + Z) and redo (Ctrl + Y) also work for Screen Overlay and Screen Backdrop changes: adding, moving, resizing, replacing, renaming, reordering and removing. The history is kept in your own browser, up to 100 steps.
Remove a Screen Overlay or Screen Backdrop
Open Screen options and choose Remove Screen Overlay or Remove Screen Backdrop. This deletes the layer and every asset on it.
In Preview and on screen
In Story Preview, Screen Overlay and Screen Backdrop content moves along with each scene transition.
On screen, video and sound on them keep playing when the scene changes, so they work well for an ambient soundtrack. Story Preview can't show that yet: there they start again at every scene change, and only play when Autoplay is on.
Scene thumbnails include them, and duplicating a story brings them along.
Each screen has its own. Their content doesn't appear on other screens.
Limits
Each Screen Overlay and each Screen Backdrop can hold up to 100 assets. These assets don't count towards the limit of assets per scene.
Good to know
Screen Overlay and Screen Backdrop are only available from Release 5. Organisations move to Release 5 on their release weekend, from 9 October.
Assets on a Screen Overlay or Screen Backdrop can't have on-click actions or triggers yet.
In Other Setups of the story, you can't reposition these assets yet.

